title: Malignancy arising in extraovarian endometriosis during estrogen stimulation.
abstract: OBJECTIVE
  Endometriosis can undergo estrogen-dependent changes similar to endometrium and may carry a risk of developing hyperplasia and carcinoma during unopposed estrogen stimulation.
  
  
  METHODS
  We reviewed the existing literature to analyze the potential of a malignancy arising from extraovarian endometriosis by estrogen stimulation.
  
  
  RESULTS
  To our knowledge, there are 20 published cases so far, with a malign transformed endometriosis during estrogen stimulation at an extraovarian site. The most common site of malignancy arising from endometriosis was the vagina (n = 5). The most common histological finding was adenocarcinoma (n = 13). The incidence of malignant transformation in extraovarian endometriosis during unopposed estrogen replacement can not be estimated based upon these case reports.
  
  
  CONCLUSIONS
  Unopposed estrogen stimulation may lead to premalignant or malignant transformation in the residual foci of endometriosis. Therefore, the addition of progestins to estrogen replacement therapy should be considered in women who have undergone hysterectomy with oophorectomy because of endometriosis, especially if they are known to have residual endometriosis.
authors.affiliation: University of Graz, Department of Obstetrics and Gynecology, Austria.
authors.forename: F
authors.initials: F
authors.lastname: Gücer
authors.forename: D
authors.initials: D
authors.lastname: Pieber
authors.forename: M G
authors.initials: MG
authors.lastname: Arikan
mesh_terms: D000230:Adenocarcinoma / Q000209:etiology; D000328:Adult; D000368:Aged; D004715:Endometriosis / Q000150:complications*; D015914:Estrogen Replacement Therapy / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009376:Neoplasms, Hormone-Dependent / Q000139:chemically induced / Q000209:etiology*; D010051:Ovarian Neoplasms / Q000503:physiopathology; D014625:Vaginal Neoplasms / Q000209:etiology